Players often talk about the rare luxury of being "in the zone" and Rory McIlroy readily admits his good fortune in having twice occupied that territory on his way to victory in two of golf's biggest events.

The Northern Irishman clinched his first major title by a staggering eight shots in last year's U.S. Open at Congressional and then replicated that winning margin as he stormed across the finish line in last month's PGA Championship at Kiawah Island.

"You can call it a trance or you can call it getting in the zone. For me, you're just very confident," world number one McIlroy told reporters on Wednesday while preparing for this week's BMW Championship.

"You've got total self-belief. You're hitting it at your target, you're hitting it close to the pins. You're seeing every putt go in.

"I've been able to do that a couple of times. Fortunately those couple of times have been in major championships and I've ended up winning them by quite a margin. Hopefully I continue to do that."

Asked how he coped mentally with being in the zone, McIlroy replied: "The most important thing when that does happen (is) you have to realize it's happening and just get out of your own way, just play one shot at a time.

"All aspects of your game are fully on. Sometimes all aspects of your game are fully on but you get in your own way and you start to thinking about it too much and you start to talk yourself out of it.

"When you're mentally in a great place, you just go with it and keep it going. But I don't care if I win by one like last week or if I win by eight like at Kiawah or Congressional. As long as your name goes on that trophy, that's all that matters."

McIlroy will tee off in Thursday's opening round at Crooked Stick Golf Club in pursuit of his fourth PGA Tour victory this year, and what would be a third in just four starts.

"I'm excited. I feel like my game is in great shape," said the 23-year-old who triumphed by one shot at the Deutsche Bank Championship on Monday to take over at the top of the FedExCup standings.

"I can't really rest or dwell on what I've done last week. I want to come out here and try as best I can again and put myself in the best possible position going to Atlanta."

This week's event is the third of four in the PGA Tour's FedExCup playoffs and only 30 players will qualify for the September 20-23 Tour Championship finale in Atlanta where the overall points winner pockets a $10 million bonus.

McIlroy has been grouped with 14-times major champion Tiger Woods, and also American Nick Watney, for the first two rounds at Crooked Stick, a marquee pairing he regards as "good fun" rather than a challenge.

"It definitely creates some more interest for the fans and for golf in general," said McIlroy. "I don't see any challenge in it.

"I think it's just good fun. It's good fun to be out there and have such an atmosphere and such a buzz around a grouping like that. It's just nice to be a part of."